Liquid pump with automatic variable suction control

ABSTRACT

THIS RELATES TO AN IMPROVEMENT IN A SUCTION PUMP AND MORE PARTICULARLY TO A GEAR PUMP USED TO PUMP FUEL OIL TO A BURNER. A PARTITION PLATE IS PLACED OVER AN ORIFICE WHICH LEADS TO A SUCTION PORT OF THE PUMP AND THE PARTITION PLATE IS PROVIDED WITH A PLURALITY OF ANGULARLY SPACED NOTCHES POSITIONED AROUND THE PERIPHERY THEREOF. THE CUMULATIVE SIZE OF ALL THE NOTCHES IS CHOSEN SUCH THAT THE VOLUME OF LIQUID WHICH CAN PASS THROUGH ALL THE HOLES IS MORE OR LESS EQUAL TO THE CAPACITY OF THE PUMP. THE   NOTCHES ENSURE THAT ANY AIR THAT IS DRAWN BY THE PUMP IS WHIPPED AROUND AND INTERMIXED WITH THE LIQUID TOL SUCH AN EXTENT THAT THE RESULTING SIZE OF THE AIR BUBBLES HAVE NO EFFECT UPON A FLAME OF THE FUEL BURNER.

Sept. 20, 1971 J. H. PETERSEN 3,606,604

LIQUID PUMP WITH AUTOMATIC VARIABLE SUCTION CONTROL Filed June 23, 1969 2 Sheets-Sheet 1 FIG.

Sept. 20, 1971 J. H. PETERSEN 5 3,606,604 LIQUID PUMP WITH AUTOMATIC VARIABLE SUC'IION CONTROL Filed June 23, 1969 2 Sheets-Sheet 2 United States Patent Office 3,606,604 Patented Sept. 20, 1971 3,606,604 LIQUID PUMP WITH AUTOMATIC VARIABLE SUCTION CONTROL Jorgen H. Petersen, Fribjerg 30, Nordborg, Denmark Filed June 23, 1969, Ser. No. 835,637 Int. Cl. F01c 1/10 US. Cl. 418-191 3 Claims ABSTRACT OF THE DISCLOSURE This relates to an improvement in a suction pump and more particularly to a gear pump used to pump fuel oil to a burner. A partition plate is placed over an orifice which leads to a suction port of the pump and the partition plate is provided with a plurality of angularly spaced notches positioned around the periphery thereof. The cumulative size of all the notches is chosen such that the volume of liquid which can pass through all the holes is more or less equal to the capacity of the pump. The notches ensure that any air that is drawn by the pump is whipped around and intermixed with the liquid to such an extent that the resulting size of the air bubbles have no effect upon a flame of the fuel burner.

This invention relates generally to an improvement for fiuid pumps and more particularly for a fuel oil pump of the type used to supply fuel to a burner.

Liquid pumps are known wherein a pump suction chamber in communication with a suction port of a pump is sub-divided by an orificed end plate which defines a flow passage for the fluid from a liquid source to the suction port of the pump. In such devices, the lower the liquid level becomes, the higher the resistance to liquid flow and therefore the larger the quantity of air delivered in a given discharge volume of the pump. This kind of pump construction is employed to insure that there is always some liquid to be pumped so that the pump does not temporarily deliver only air.

In the known pump constructions, the suction chamber of the pump is generally centrally located and the orifice in the end plate usually consists of a slot extending radially from the center or the orifice may consist of several bores arranged along a common radius. The operation of such pumps may be impaired if the radial slot is situated too low because the end plate has been mounted the wrong way or because the pump is capable of being mounted in more than one position and has been improperly mounted. Difliculties may also arise when an eccentrically located suction chamber, an arrangement employed in many types of pumps, is not positioned correctly relative to the radial slot.

-It is a principal object of the present invention to provide a new and improved suction chamber arrangement in a fluid pump obviating the disadvantages of known pumps and having means in the suction chamber for precluding the complete exhaustion of the supply liquid from the suction chamber and consequent loss of liquid suction and thereby precluding delivery of only air by the pump.

Another object of the invention is to provide means for controlling the size of air bubbles entrained in the liquid which is drawn into the suction port of the pump to ensure a substantially continuous flow of liquid discharged from the pump. This is particularly important when the pump is being used to supply fuel oil to a burner and such means ensures that the burner flame will not pulsate in accordance with the volume of air contained in the pump output.

A further object of the invention is to provide an improved apparatus which ensures that neither the angular position of the pump or the relative angular position of the end plate will impede the desired air-to-liquid ratio as the liquid level rises or falls in the suction chamber so that loss of liquid suction is avoided.

In order to carry out the objectives of the present invention, the pump is provided with a suction chamber subdivided into inner and outer sub-chambers by a partition plate having notches therein. The notches are angularly spaced around the periphery of the partition and the partition is positioned within the suction chamber such that the liquid must flow from the outer sub-chamber through the notches to the inner sub-chamber before it can enter the orificed end plate leading to the pump suction port. The notches are arranged so that more or less of them are exposed to the air as the liquid level falls or rises, respectively. As the number of notches having liquid flowing therethrough decreases, more notches will have air flowing therethrough. But the increased volume of air which is drawn in by the pump is whipped around and intermixed with the liquid in the inner sub-chamber to such an extent that the resulting air which is entrained in the liquid entering the suction port of the pump is wholly made up of minute air bubbles which are so small in size as to not disturb the burner flame.

In a preferred embodiment of the invention, the suction chamber is subdivided by a round partition symmetrically arranged about an axis of the pump and having radially extending peripheral notches therein. The partition is removably keyed in place and variably changes the resistance to liquid fuel flow to an orificed end plate.

Other objects and advantages of the present invention will become apparent after reading the following specification and appended claims when taken in conjunction with the following drawings in which:

FIG. 1 is a fragmentary longitudinal sectional view of a pump provided with a suction chamber arrangement in accordance with the invention;

FIG. 2 is a plan view of a partition element used in the arrangement disclosed in FIG. 1;

FIG. 3 is a schematic side view of a prior art suction chamber;

FIG. 4 is a schematic side view of a suction chamber employing the partition element of the present invention; and

FIG. 5 is a plan view of the partition element shown in FIG. 4.

As illustrated in the drawing, a motor 1 is connected to drive a pump 2 which has a dished end cover 3 which circumferentially encloses the pump 2, as seen in FIG. 1. Positioned within the pump cover is in annular filter 4 which filters out undesirable contaminants in the liquid. A diaphragm 5, constructed of a suitable material such as rubber, is held against an open end of the filter 4 means of an inwardly extending annular projection (not numbered) which is integral with the dished end cover 3. The diaphragm 5 is positioned over the annular projection forming an air space or buffer zone 6 therebetween, as well known in the art. The pump is provided with an inlet 7 in communication with a source of liquid, for example a fuel oil source (not shown), and an annular chamber 8 in communication with the inlet 7. A suction chamber 9 is separated from the annular chamber 8 by the filter 4 and this ensures that all the liquid flowing through the pump will first undergo a filtering operation.

The pump is provided with an end plate 10 having a recess 11 which is in communication with an orifice 12. The orifice 12 leads directly to the suction port of the pump. A curved partition 13 completely covers the recess 11 and subdivides the suction chamber 9' into an outer sub-chamber 14 and an inner sub-chamber 15.

The partition 13 has an arcuate cross section and a circular peripheral configuration. It is to be understood that any peripheral configuration may be used in practicing the present invention, but for the purposes of the following discussion, a circular peripheral configuration was chosen. A plurality of radially extending notches 16 are uniformly positioned around the periphery of the partition 13, as seen in FIG. 2. Any number of notches may be employed; however, in the example illustrated eight are used. The partition 13 is mounted on the end plate such that it completely covers the sub-chamber and is anchored in place against rotational movement by means of a projection 17 which extends into one of the notches 16.

The operation of the invention will now be described with reference to FIGS. 3-5. In FIG. 3 is shown an end plate 10 having an orifice 12' therein of a typical prior art pump. With the liquid level as shown, large amounts of air are drawn into the suction chamber of the pump along with the liquid and the air will exist as large bubbles or slugs of air in the pressurized output liquid exiting from the pump. If the pump is used to pump fuel oil to a burner, the bubbles of air will disturb the flame in such a way that the flame will pulsate in accordance with the amount and size of air bubbles in the fuel oil. If the liquid level drops a slight amount or if the flow rate through the pump increases, more air will be discharged by the pump with the detrimental elfect that the flame may be extinguished. If the liquid level drops below the level of orifice 12', the pump will then pump only air and such a condition could be detrimental to the apparatus to which the liquid is being pumped, for example a fuel oil burner.

The present invention is intended to obviate the above detrimental elfects and does so by normally maintaining the liquid level at a slightly higher level than possible with the type of prior art pump disclosed in FIG. 3 and by premixing and uniformly dispersing the air which is drawn in by the pump with the liquid in the inner subchamberlS in such a way that the air-liquid mixture will be whipped around sufficiently to reduce the size of the air bubbles to such an extent that they will be too small to have an effect on the burner. The notches 16 are carefully dimensioned in accordance with the ca pacity of the particular pump. The summation of all the notches 16 is chosen such that the volume of liquid flowing therethrough is substantially equal to the volume flow through the pump. This means that for the same flow rate, the liquid level in FIG. 4 must of necessity be higher than the liquid level of the prior art pump in FIG. 3

since liquid must flow through almost all the notches 16 in order to have a sufiicient flow area to handle the given flow rate. This is due to the fact that the liquid which can pass through all the notches 16 is more or less equal to the capacity of the pump, as aforementioned.

As seen in FIGS. 4 and 5, any air which is drawn through orifice 12. enters through the uppermost notch and is whipped around by the liquid motion in inner sub-chamber 15 to such an extent that the size of the air bubbles entrained in the liquid exiting through orifice 12 is small enough so as not to affect the flame of a burner. Without the partition 13, the air which is drawn through orifice 12 and delivered to the suction port of a pump exists in the liquid as relatively large bubbles and as pointed out above, such bubbles have a detrimental effect upon a burner flame. By use of the partition plate 13, the air which is delivered to the pump suction port exists in the liquid as very fine bubbles which are ineffective to cause pulsation in the burner flame. As the liquid level decreases or drops in FIG. 4, the number of notches available for flow of liquid therethrough also reduces and the amount of air which is drawn through orifice 12 increases since more notches 16 are exposed above the liquid level. The air entering through the upper exposed notches must pass through the swirling liquid in inner sub-chamber 15 before reaching orifice 12 and as delineated upon above, the air is whipped around and intermixed with the liquid to such an extent that the air bubbles which exit through orifice 12 and enter the suction port of the pump are of such a reduced size as to have substantially no effect upon a burner flame and suction loss of the liquid at the pump is accordingly minimized. This avoids the possibility that the pump will temporarily pump only air as such a condition could be detrimental to the apparatus to which the liquid is being delivered.

The arrangement of the notches 16 around the periphery of the partition 1.3 is important and is selected to create sufiicient liquid turbulence in inner sub-chamber 15 to whip the air into time bubbles. As seen in FIGS. 4 and 5, the liquid is drawn through all of the notches which are beneath the liquid and converges toward orifice 12. In the inner sub-chamber 15, the surface of the partition 13 between adjacent notches 16 and the adjoining surface of the end plate 10 create a static boundary condition for the liquid flowing towards orifice 12 and such helps create the formation of turbulent eddy currents in the inner sub-chamber 15. This causes the liquid in inner sub-chamber 15 to swirl sufficiently to whip the air into fine uniformly dispersed bubbles with the attendant result that loss of liquid suction at the pump inlet is substantially prevented despite momentary rising or falling of the liquid level.

What I claim and desire to secure by Letters Patent is:

1. An improved pump assembly comprising: a pump operable to deliver a predetermined volume therethrough; means defining. a combined reservoir and suction chamber disposed upstream from said pump which may fill with a liquid to a predetermined minimum level, an end wall constituting a boundary portion of said reservoir and suction chamber and having a suction orifice therein at a height below said predetermined minimum level; a curved partition plate having a plurality of notches therein and being in surrounding relation to said suction orifice, said plate dividing said chamber into inner and outer subchambers; said plate serving to intermix liquid and air drawn from said outer subchamber to said inner subchamber into a liquid containing minute air bubbles uniformly dispersed therein thereby preventing the delivery of air slugs in the pump output; the combined effective area of all of said notches being preselected to permit a volume of liquid to flow therethrough substantially equal to said predetermined volume of said pump.

2. An improved pump assembly according to claim 1 wherein said partition plate has a circular configuration, a curved cross-section, and said plurality of notches are angularly spaced around the periphery thereof.

3. An improved pump assembly according to claim 2 wherein said end wall has a recess therein; and said partition plate is mounted against angular rotation in said recess.

References Cited UNITED STATES PATENTS 1,778,923 10/1930 Taurisano 261-28 1,921,895 8/1933 Taurisano 261-28 1,933,820 11/1933 Mueller 261-28 1,996,789 4/1'935 Baker 261-28 1,964,942 7/1934 Hallgarth 261-76 3,323,249 6/1967 Randall 261-121 1,970,082 8/1934 Ellehammer 261-121 3,467,072 9/1969 Toesca 261-76 WILLIAM L. 'FREEH, Primary Examiner US. Cl. X.R. 417-503; 418-15 

